NEW YORK--Carly Fiorina surged toward the top of social media ranks during CNN's Republican debate, emerging as the second-most tweeted candidate and finishing in the top four in a Thomson Reuters gauge of social media sentiment. Stealing much of the spotlight from persistent social media leader Donald Trump, Fiorina also had one of the most tweeted moments of the Wednesday night debate with her challenge of the GOP front-runner over his reported remark on her looks. According to a Thomson Reuters measure of social media mentions, Fiorina, who was a late addition to the second prime-time Republican debate, emerged as the second most tweeted candidate with 19,400 tweets, following Trump with 35,312 tweets. In addition, Fiorina's social media score - a computation of the variation between positive and negative tweets - placed her in the top four of the candidates on the stage during the three-hour event on CNN. Her score averaged 6.3. A score above zero indicates net positive sentiment. Ben Carson finished atop the sentiment ranks with a score of 10.4, although he garnered less than half the traffic seen by Fiorina. He was followed by John Kasich at 9.7, who only had a fraction of Fiorina's traffic, and Trump at 8.3. Among other candidates, Marco Rubio ended the night with an average social media score of 5.5 after surging as high as 21.06 during the last hour of the debate, and Chris Christie finished with a score of 2.1. Three of the 11 candidates ended the night with negative sentiment scores: Mike Huckabee at negative 16.6, Scott Walker at negative 5.1, and Ted Cruz at negative 2.6. Meanwhile, Jeb Bush and Rand Paul ended barely in the positive territory. Social media has become more important than ever for the crowded field of candidates vying to become president, and the campaigns battle for prominence on platforms like Twitter and Facebook. Using a proprietary algorithm, Thomson Reuters classifies Twitter posts mentioning candidates' full names or their official Twitter handles and then derives scores from the volume of tweets identified as positive, neutral or negative in a set period. Reuters measured the candidates' sentiment scores at the end of each hour of the debate and then over the entire event. At one stage, as Fiorina confronted Trump over his recent "Look at that face! Would anyone vote for that?" remark, her sentiment score reached as high as 14.08. Trump's sank as low as 1.07 around the same time. That exchange also prompted a flurry of activity on Google, with "What did Donald Trump say about Carly Fiorina" emerging as one of the top search terms during the debate. Other top social media moments included Jeb Bush's admission of marijuana use 40 years ago and the candidates' stance on Kim Davis, the county clerk from Kentucky who was jailed after refusing to issue marriage licenses to same-sex couples.